1. Field of the Invention
The present invention relates to a method of fabricating an active device array substrate, and more particularly, to a method of fabricating the active device array substrate by using a multi-tone mask.
2. Description of Related Art
Nowadays, the multimedia technology has been well developed, which mostly benefits from the development of semiconductor devices or display apparatuses. As for the display, the thin-film transistor liquid crystal display having superior features, such as high definition, good space utilization efficiency, low power consumption and no radiation, has become the mainstream of the market.
The thin-film transistor liquid crystal display mainly comprises a thin film transistor array substrate, a color filter plate and a liquid crystal layer disposed between the two substrates. The thin-film transistor array substrate is mainly formed by five mask processes. For example, in the conventional five mask processes, the first mask process mainly defines the gate and scan line; the second mask process mainly defines the channel layer; the third mask process mainly defines the source, drain, and data line; the fourth mask process mainly defines the passivation layer; and the fifth mask process mainly defines the pixel electrode. The number for performing the mask process directly influences the cost and tack time of fabricating the thin-film transistor array substrate such that companies in the industry all try to develop a method to reduce the number of the mask processes. In order to increase the throughput and lower the manufacturing cost, it is required to improve the manufacturing process of the thin-film transistor array substrate.